In the past, in manufacturing of long objects such as a film, a sheet, and a fiber (hereinafter, referred to as an object), a heat treatment device configured to continuously heat-treat the object has been known. As an example of a case of carbon fiber, the heat treatment device continuously performs the heat treatment of the precursor fiber made of, for example, polyacrylonitrile fibers, within a heat treatment chamber. At this time, a cracked gas such as cyanide, ammonia, and carbon monoxide is generated in the heat treatment chamber by oxidation reaction of the precursor fiber. It is necessary to recover the cracked gas and perform a gas treatment such as a combustion treatment.
Patent Document 1 suggests a heat treatment device in which in order to prevent such a cracked gas from leaking to the outside of the heat treatment device from an loading opening/an unloading opening of the precursor fiber bundle of the heat treatment device, a seal chamber configured to set a negative pressure in the chamber and recover the cracked gas is provided near the heat treatment chamber, and an air curtain unit is provided which suppresses the inflow of outside air by blowing the air outside the heat treatment device toward the object on the outside of the loading opening/unloading opening of the precursor fiber bundle of the seal chamber, wherein a cylindrical rectifying member is provided in the seal chamber continuously provided to the heat treatment chamber so as to prevent the gas in the seal chamber from leaking to the outside even if the ejection velocity of the air blowing toward the object is increased.
In addition, a heat treatment device, in which in order to suppress a temperature variation in the heat treatment device, a slit is provided in the leading opening/unloading opening of the heat treatment device, and which is provided with a mechanism configured to eject the heated air to the inside of the heat treatment device or the outside of the heat treatment device from the slit, has been suggested (see, Patent Document 2).
In order to prevent the cracked gas from leaking to the outside of the heat treatment device from the loading opening/unloading opening of the precursor fiber bundle of the heat treatment device, a heat treatment device provided with an air curtain unit configured to suppress the inflow of outside air by blowing the air outside the heat treatment device toward the object on the outer side of the loading opening/unloading opening of the precursor fiber bundle has been suggested (see Patent Document 3).